Hi. I have had great success with Forever Black (FB) on scuttle and other cars that have severely faded black trim. I first used it sometime ago on the scuttle and the first couple of coats lasted around 3 months which was a bit disappointing initially (may have been my prep) but I then added another couple of coats and it has lasted me 18 months so far with no sign of fading. It is easily applied with the provided sponge on a stick but wear gloves to keep the dye/paint off your hands. I have seen great reviews of ‘Solution Finish’ (SF) but some reviewers are torn between SF or FB for best longevity. Neither are cheap £15 for FB and similar for a 1oz bottle of SF but plenty of YouTube videos out there to help you decide whether dye products are your thing or just ‘paint-and-forget’. 2007 3.6 HSE Java
2014 Evoque Dynamic Fuji 2.2 (SHMBO’s)
2000 Discovery 2 GS
1980 Series 3 2.25 petrol Rag top

Well being a Auto Painter/Panelbeater i've tried about everything, BUT this stuff in the link is the ducks guts (damn good)
Brings your grey plastic back to black

https://www.lithiumautocare.com.au/product...trim-serum

Lithium's Best Black Trim Restorer, Rejuvenator & Protectant
Restores to original colour
Formulated to outlast all others
Shields against UV rays
Soulmate of all rubbers and plastics
Transforms weathered & oxidised trim, rubber & plastic in seconds

Can be purchased all over the place.